A man brandished a gun at terrified customers and staff at a south London kebab shop in Tulse Hill last weekend.
He is alleged to have threatened people in the shop before leaving.
After police were called, the suspect returned and reportedly threatened the unarmed officers. He was tackled to the ground and taken to hospital.
The gun and six rounds of ammunition were recovered at the scene.
Matt Bell, borough commander of Lambeth, said: “Incidents such as this demonstrate the lengths that police officers go to on a daily basis in the fight against crime.
“The unarmed officers who tackled this suspect showed incredible bravery and put their lives on the line in order to protect the public.”